Anthonyexmouth

Just now, Rocket Stars said:

Im not sure. But could be to long exporsure. I use Sharpcap to mersure this. It usally gives me very short exporsures. I can highly recommend sharpcap for sensorananlysis ect! Cost nothing to use. Pro version is 15quid, If i dont remember wrong. 

Yeah i got sharpcap pro, use it for my PA, issue is that a lot of people have said the 294 needs longer exposure flats, just not sure how long is too long or too short. 

6 minutes ago, ollypenrice said:

Probably somewhat target dependent. I think your camera is colour so you won't be a narrowband specialist? It is easier for more basic optics to give a good image through NB filters because the light is almost monochromatic. In colour imaging you'll see the biggest difference with the upgrade. Images including insistent starfields will give an easily perceptible difference. For all that, the ED80 is no slouch and punches above its weight. Then again, in the Apo world, the Esprits punch above their price.

Olly

I think the thing i'm looking forward to the most is a nice focuser, my ED80 was second hand and struggled with slipping/shifting since i owned it. tried all the usual tweaks

8 minutes ago, ollypenrice said:

Much better colour correction, particularly in blue. Smaller, tighter stars. Fascinating black hole in your bank account. What astronomer could resist such temptations?

Olly

So is it a very noticeable upgrade or one of those "expert eyes" can tell the difference?

So, I've read that the ASI294mc Pro likes to have slightly longer flats. I've got a little EL panel and darkened it a little with a few sheets of paper as it was too bright. 

At the moment to achieve 25000adu im getting 4.5 secs exposures, should I remove a few sheets or will this be ok/preferable?

heres the histogram from Gimp, debayered

15 minutes ago, vlaiv said:

Although large imaging circle refers to optics correction rather than vignetting - in most cases larger imaging circle means larger unvignetted portion.

You should not concern your self with corner vignetting - it is not related only to telescope, sometimes other parts of system can introduce a bit of vignetting - like correctors and filters unless they are very large, but in any case - flat fielding solves that.

not that concerned but just looking at and counting the advantages to justify splashing out £1600. 

does a larger imaging circle eliminate vignetting? Anyone know how much bigger the SW esprit 100 is compared to the ED80? Thinking the esprit is going to be my next scope and wondering what the improvements are going to be over my humble ED80. 

1 hour ago, woodblock said:

These bolts on my mount are very stiff. They've been like that from the beginning. Not only that but they are also what I can only describe as Squidgy. When I try to tighten them up fully after making an adjustment they don't tighten up 'hard'. I'm afraid to over tighten. Is this normal? Are they all like that?

Cheers

Steve

 

they ain't great, just make sure the opposite bolt is loose as you adjust then lightly nip the top bolt when polar aligned. 

On 26/03/2020 at 15:46, Astrofriend said:

Hi,
Have you noticed how advanced Gimp has been with the new version 2.10 ?

Now it work perfekt to open Fits 32 bit floating point images and process them. I have tried this many times earlier but it never worked very good. Now it's like a dream to work with.

I'm in the learning process how to use Gimp's capabilities. I have now got the opening process of three grey rgb images to work. It's of course not very complicated, but for me who never used Photoshop or something simular it was and I had hard to find a tutorial for the new version.

I have now made a tutorial for this first step how to start with Gimp and open 32 bits separated color images:
http://www.astrofriend.eu/astronomy/tutorials/tutorial-gimp-astrophotography/01-tutorial-gimp-astrophotography-introduction.html

If you already working with Gimp, have you found something of special interest ?

Lars

Maybe I'm being a bit dumb, but how do you open OSC fits images in Gimp? when i try i only get greyscale images. 

4 minutes ago, edarter said:

interesting, I'm using DSS but when I tried it with two frames as an experiment having spotted the potential issue, it threw up an error saying only one of the two frames would be stacked?!?

 

that will most probably be because of the % to stack option. If that was set to 100% it would probably do it, default is 80%

Can't find any mention of Dark Optimisation in APP, anyone know if there is an option for that in APP?

2 minutes ago, vlaiv said:

What software did you use to stack this with?

Maybe you did not load calibration files? This image shows both issues with flats - dust shadows and issues with darks - there is amp glow visible in top right corner.

This could happen if you forgot to add calibration files or like I said, dark optimization was turned on for stacking and messed up dark calibration (hence both flat problems and visible amp glow).

 

If that was the autosave.tiff then DSS, otherwise it may be either DSS or APP thats then been tweaked in Gimp. 

3 minutes ago, vlaiv said:

The one you used to calibrate / stack resulting image that shows dust shadows.

I'm guessing that you used same data as first stack. First stack does not show any issues with flat calibration - which means flats are fine.

Dark optimization works by scaling darks - something that you can do only if you use bias files and bias are stable enough (this seems not to be the case with CMOS sensors / cameras as far as I can tell). For this reason it is best to turn this option off as it can cause issues with flat calibration.

 

just checked DSS and dark optimisation was unchecked. 

Just now, Concretedan said:

Hi There,

There were 89 subs at 45 seconds

Thanks

 

45secs seems incredibly short. 

Just now, discardedastro said:

Just more of them, I think, though hard to say without seeing an individual sub.

L_2020-03-26_20-58-12_180s_294mc__Color_G125_OFS22.fit

As Mark says, Deep Sky Stacker sorts out the alignment for you even if its 180 degrees out. 

2 minutes ago, Johns22 said:

Thanks, I will try the east heavy balance tonight. I have entered 190mm for the focal length of the guidescope (following advice on others using the standard 50mm finder on here with the camera). If I get chance before setting up tonight, I'll post the guide log file. The imaging camera is a Canon 600D unmodified.

Cheers

John.

Wind or even a light breeze may be your problem too rather than a technical issue. That thing is gonna be a sail on that mount. 

2 minutes ago, discardedastro said:

Gave this a go in PI - there's not much in terms of SNR between the fainter areas of nebulosity so a bit more exposure time will help that, but it's otherwise fairly clean data. Vignetting might be tilt, in which case you can get a tilt adapter for T2 trains - Teleskop Express do one - but it isn't significant and if you do flat fielding correctly should calibrate out nicely. Same goes for the dust motes, though cleaning is always preferable!

Thats good to know, I was running 3min subs on this with my 294mc pro. would longer subs be beneficial? don't want to swamp it or just more of them? 

5 minutes ago, simmo39 said:

WEll ill give that a try tonite and see what I get. The only thing Im not to sure of is the actule sub length to us for the flats. I have read all the thearoy stuff on flats and I have to say a lot of it is over my head but will give it a try.

I'll be watching for the answer to this myself, been using APT for my flats too and maybe it's time to try a new method. 

1 minute ago, vlaiv said:

That is issue with calibration procedure. Probably faulty application of darks. If you used dark optimization it could produce this effect.

Btw - dust will be on sensor / filters and not on telescope optics.

Would that be dark optimisation in DSS or APP?

How much data did you collect, sub length and number?

40 minutes ago, tico said:

Hi,
It is the most economical of all 100mm, is the 25X100 binocular for deep sky observation really worth it?

Regards,

Tico.

 

What is your budget? what are you hoping to see?

I own a pair of revelation astro 25x100 and love them but i'm mainly an imager so don't get used much, if i was going visual on a budget i'd aim for the largest dob i could afford/handle/store. 

3 minutes ago, Concretedan said:

Hi All,

 

I'm still new to astrophotography and learning all the time but I need some advice if possible please?  Could you have a look at the image below and tell, if you can, what the misting and black spots may be please?

Every time I try and brighten the image using GIMP (moving the curves line to the top left) it highlights this misting and the spots.

I am taking darks, flats, etc. as per the instructions on the Sharpcap website.

As I said I'm new to all this really so please be gentle with me!

Any advice gratefully received.  Thank you.

 

I've been at this 3 yrs and only just getting started on the processing, let everyone here know the setup you're using and some details on the specs of the subs you've taken and stacked. Also if you post the stacked image as a tiff so people can have a play themselves and get a better idea if its data thats the problem or the processing.

HTH

I often notice when stretching the image that vignetting seems biased to one side, is there a way to correct this every easily on the SW ED80? Is it a collimation issue or just a result of the stock focuser? 

Also, had another go with APP and ended up with this. Seem to have a few large dust motes but looking at the optics I can't see any specks. Really annoying. 

1 minute ago, geeklee said:

Here's some work in APP Anthony as you mentioned that software.  Just Light Pollution Removal and resize (50%) + rotate.  Saved with the 15%, 3 Sigma, 0.0% base DDP stretch (so a bit much prob!)

thanks, with the tools in APP i've never really understood where the requested boxes should be placed on the image. 

1 hour ago, alacant said:

Hi

Here are the stretched, darkened-blurred, mask and final images. To lose the gradient, subtract the blur from the stretched, then process it to taste. 

HTH

EDIT: don't forget to mask the stars before you stretch any more;)

that looks really nice, can you tell me the process and software used.